What is 100 factorial?

100 factorial, written as 100!, is the product of all positive integers up to 100. It's an extremely large number: 93326215443944152681699238856266700490715968264381621468592963895217599993229915608941463976156518286253697920827223758251185210916864000000000000000000000000. It's like multiplying a really long list of numbers!